Furthermore, to differentiate between the contours of the normal and suspicious items, the custom shape-preserving (SPB) and identity blocks (IB) have been added within the encoder topology. The SPB, as depicted in Figures REF  and REF  (A), integrates the multi-scale tensor map (after scaling) in the feature map extraction to enforce further the attention on prohibited items' outlines. The IB (Figure REF -A), inspired by ResNet architecture [1]}, acts as a residual block to emphasize the feature maps of the previous layer.
